NEW YORK — Microsoft knows the cell phone world is where it's happening, and it's determined to be a part of it. After years of declining sales of phones based on Microsoft's Windows Mobile software, the company is starting with a fresh slate — a completely new operating system for phones.

The new handsets will go up against Apple's highly popular iPhone and the expanding number of phones running on Google's Android operating system.

The first phone with Windows Phone 7 will be the Samsung Focus, which hits AT&T stores Nov. 8 for $200 with a two-year contract requirement, Microsoft said Monday. It will be closely followed by two more phones for AT&T, made by LG Electronics and HTC and one for T-Mobile USA, also made by HTC.

In May, Microsoft launched another new phone software package, Kin, only to yank it about two months later in the face of dismal sales. Windows Phone 7 is a different beast, and Microsoft is putting its full weight behind it.

In all, Microsoft announced nine phones for the U.S. market on Monday, including one from Dell and it has lined up 60 carriers in 30 countries to carry Windows 7 phones. Another U.S. carrier, Sprint Nextel is getting a Windows 7 phones in the first half of next year.

In the most recent quarter, Microsoft's older system, Windows Mobile, accounted for just 5 percent of the worldwide smart phone market.